Evolution of the sintering ability, microstructure, and cell performance of Ba_0.8Sr_0.2Ce_0.8−x−yZr_yIn_xY_0.2O_3−δ (x = 0.05, 0.1 y = 0, 0.1) proton-conducting electrolytes for solid oxide fuel cell

Abstract

Ba_0.8Sr_0.2Ce_0.8−x−yZr_yIn_xY_0.2O_3−δ (x = 0.05, 0.1 y = 0, 0.1) proton-conducting oxides are prepared using a solid state reaction process. The effect of indium contents on the microstructures, chemical stability, electrical conductivity, and sintering ability of these Ba_0.8Sr_0.2Ce_0.6Zr_0.2In_xY_0.2−xO_3−δ oxides were systemically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and two probe conductivity analysis. The results reveal that the Ba_0.8Sr_0.2Ce_0.6Zr_0.2In_xY_0.2−xO_3−δ oxides are cubic perovskite crystal structure without second phase. Surface morphology of 1450°C, 4 h sintered oxides shows a dense microstructure. The optimum conductivity of Ba_0.8Sr_0.2Ce_0.75In_0.05Y_0.2O_3−δ oxide is 0.011 S/cm measured at 800°C. Chemical stability of the oxides to resist CO₂ at 600°C is effectively improved by doping 0.1 at % indium or more. In addition, the laminated electrolyte and anode layers which fabricated by tape casting were co-sintered at 1450°C for 4 h. The sintered half-cell coated with Pt paste as cathode was used for I–V curve performance testing. The performance of the single cell of anode supported proton-solid oxide fuel cell (P⁺-SOFC) have powder density of 139.8 mW/cm at 800°C. Therefore, the Ba_0.8Sr_0.2Ce_0.75In_0.05Y_0.2O_3−δ ceramic is suggested to be a potential electrolyte material for P⁺-SOFC applications.